Renin is a proteolytic enzyme produced and secreted into the bloodstream by the juxtaglomerular cells of the kidney. In the bloodstream, renin cleaves a peptide bond in the serum protein angiotensinogen to produce a decapeptide known as angiotensin I. A second enzyme known as angiotensin converting enzyme, cleaves angiotensin I to produce the octapeptide known as angiotensin II. Angiotensin II is a potent pressor agent responsible for vasoconstriction and elevation of cardiovascular pressure. Attempts have been made to control hypertension by blocking the action of renin or by blocking the formation of angiotensin II in the body with inhibitors of angiotensin I converting enzyme.
Classes of compounds published as inhibitors of the action of renin on angiotensinogen include renin antibodies, pepstatin and its analogs, phospholipids, angiotensinogen analogs, pro-renin related analogs and peptide aldehydes.
A peptide isolated from actinomyces has been reported as an inhibitor of aspartyl proteases such as pepsin, cathepsin D and renin [Umezawa et al, in J. Antibiot. (Tokyo), 23, 259-262 (1970)]. This peptide, known as pepstatin, was found to reduce blood pressure in vivo after the injection of hog renin into nephrectomized rats [Gross et al, Science, 175, 656 (1971)]. Pepstatin has the disadvantages of low solubility and of inhibiting acid proteases in addition to renin. Modified pepstatins have been synthesized in an attempt to increase the specificity for human renin over other physiologically important enzymes. While some degree of specificity has been achieved, this approach has led to rather high molecular weight hepta- and octapeptides [Boger et al, Nature, 303, 81 (1983)]. High molecular weight peptides are generally considered undesirable as drugs because gastrointestinal absorption is impaired and plasma stability is compromised.
Short peptide aldehydes have been reported as renin inhibitors [Kokubu et al, Biochim. Biophys, Res. Common., 118, 929 (1984); Castro et al, FEBS Lett., 167, 273 (1984)]. Such compounds have a reactive C-terminal aldehyde group and would likely be unstable in vivo.
Other peptidyl compounds have been described as renin inhibitors. EP Appl. #128,762, published 18 Dec. 1984, describes dipeptide and tripepride glyco-containing compounds as renin inhibitors [also see Hanson et al, Biochm, Biophys, Res. Comm., 132, 155-161 (1985), 146, 959-963 (1987)]. EP Appl. #181,110, published 14 May 1986, describes dipeptide histidine derivatives as renin inhibitors. EP Appl. #186,977 published 9 Jul. 1986 describes renin-inhibiting compounds containing an alkynyl moiety, specifically a propargyl glycine moiety, attached to the main chain between the N-terminus and the C-terminus, such as N-[4(S)-[(N)-[bis(1-naphthylmethyl)acetyl]-DL-propargylglycylamino]-3(S)-h ydroxy-6-methylheptanoyl]-L-isoleucinol. EP Appl. #189,203, published 30 Jul. 1986, describes peptidyl-aminodiols as renin inhibitors. EP Appl. #200,406, published 10 Dec. 1986, describes alkylnaphthylmethylpropionyl-histidyl aminohydroxy alkanoates as renin inhibitors. EP Appl. #216,539, published 1 Apr. 1987, describes alkylnaphthylmethylpropionyl aminoacyl aminoalkanoate compounds as renin inhibitors orally administered for treatment of renin-associated hypertension. PCT Application No. WO 87/04349, published 30 Jul. 1987, describes aminocarbonyl aminoacyl hydroxyether derivatives having an alkylamino-containing terminal substituent and which are described as having renin-inhibiting activity for use in treating hypertension. EP Appl. #300,189 published 25 Jan. 1989 describes amino acidmonohydric derivatives having an alkylamino-alkylamino N-terminus and a .beta.-alaninehistidine or sarcosyl-histidine attached to the main chain between the N-terminus and the C-terminus, which derivatives are mentioned as useful in treating hypertension. U.S. Pat. No. 4,902,706 which issued 13 Feb. 1990 describes a series of histidineamide-containing amino alkylaminocarbonyl-H-terminal aminodiol derivatives for use as renin inhibitors. U.S. Pat. No. 5,032,577 which issued 16 Jul. 1991 describes a series of histidineamide-aminodiol-containing renin inhibitors.
Several classes of sulfonyl-containing amino-diol renin-inhibitor compounds are known. For example, EP #229,667 published 22 Jul. 1987 describes generally alkylsulfonyl histidineamide amino diol C-terminated-alkyl compounds as renin inhibitors. Australian Patent Application #30797/89 published 7 Sep. 1989 describes alkylsulfonyl histineamide amino diol C-terminated-alkyl compounds as renin inhibitors, such as (S)-.alpha.-[(S)-.alpha.-[(t-butylsulphonyl)methyl]hydrocinnamamido]-N-[(1 S,2R,3RS)-1-(cyclohexylmethyl)-2,3-dihydroxy-4,4-dimethylpentyl]-imidazole- 4-propionamide and (S)-.alpha.-[(S)-.alpha.-[(t-butylsulphonyl)methyl]hydrocinnamamido]-N-[(1 S,2R, 3S, 4RS)-1-(cyclohexylmethyl)-2,3-dihydroxy-4-methylhexyl]imidazole-4-propiona mide. U.S. Pat. No. 4,914,129 issued 3 Apr. 1990 describes sulfone-containing amino-hydroxyvaleryl compounds for use as antihypertensive agents, such as the compounds N[2(S)-benzyl-3-tert-methylsulfonylpropionyl]-His-Cha-Val-n-butylamide and N-[2(R)-benzyl-3-tert-methylsulfonylpropionyl]-His-Cha-Val-n-butylamide. EP #416,373 published 13 Mar. 91 describes alkylsulfonyl histidineamide amino diol compounds as renin-inhibitors, such as (S)-.alpha.-[(S)-.alpha.-[(tert-butylsulfonyl)methyl]hydrocinnamamido]-N-[ (1S,2R,3S)-1-(cyclohexylmethyl)-3-cyclopropyl-2,3-dihydroxypropyl]-imidazol -4-propionamide and (S)-.alpha.-[(S)-.alpha.-[(tert-butylsulfonyl)methyl]-hydrocinnamamido]-N- [(1S,2R,3R/S)-1-(cyclohexylmethyl)-3-cyclopropyl-2,3-dihydroxybutyl]imidazo l-4-propionamide.
Propargyl-containing amino diol compounds for treatment of hypertension are described in U.S. Application Ser. No. 07/783,955 of G. J. Hanson et al filed on 29 Oct. 1991.